Twisted Pair Of Insulated Wires Senses Moisture
Eric G. Laue, James B. Stephens · NASA Tech Briefs · 1989
Sensitivity of electronic moisture sensor to low levels of moisture increased by new electrode configuration. Moisture-sensing circuit described in Low-Cost Humidity Sensor (NPO-16544). New twisted pair of wires takes place of flat-plate capacitor in circuit. Configuration allows for thermal expansion and contraction of polymer while maintaining nearly constant area of contact between polymer and wires.